PVDF Butterfly Valve
This Polyvinylidene Fluoride (PVDF) butterfly valve is designed for quarter-turn isolation and flow control in aggressive chemical and high-purity fluid lines. It features a fully molded PVDF body and disc paired with a choice of elastomeric backings (EPDM, FPM/Viton) or encapsulated PTFE seals.
Description
Product Overview
This Polyvinylidene Fluoride (PVDF) butterfly valve is designed for quarter-turn isolation and flow control in aggressive chemical and high-purity fluid lines. It features a fully molded PVDF body and disc paired with a choice of elastomeric backings (EPDM, FPM/Viton) or encapsulated PTFE seals. The design keeps all wetted surfaces strictly non-metallic, preventing ion contamination and metallic corrosion.
The wafer and lug designs fit standard pipe dimensions without thermal distortion during process cycling. Integrated ISO 5211 mounting pads allow direct conversion from manual levers to automated pneumatic or electric actuators.
Key Product Characteristics
Full-Corrosion Barrier: Wetted body and stem zones are protected by virgin PVDF and fluoropolymer seals, resisting strong acids, chlorine solutions, and organic solvents.
Low Metal Ion Extraction: Manufactured from unpigmented resin without plasticizers or metal stabilizers, meeting pure water system requirements.
Thermal Stability: Retains structural integrity and dimensional stability up to 120 deg C (248 deg F) continuous operational load.
ISO 5211 Direct Mounting: Top-flange geometry accepts standardized actuator brackets without extra stem extensions or mounting kits.
Streamlined Disc Geometry: Low-profile disc profile lowers flow resistance coefficient (Cv) and minimizes local turbulence at full opening.
Dual-O-Ring Stem Sealing: Secondary FPM/EPDM shaft seals isolate external mechanical hardware from internal process fluids.
Key Specifications
|
Parameter |
Specification |
Standard / Reference |
|
Size Range |
DN40 to DN300 (1-1/2" to 12") |
ISO 6708 / ASME B16.10 |
|
Pressure Rating |
PN10 (10 bar / 145 psi @ 20 deg C) |
DIN EN 1333 / ASTM F1970 |
|
Operating Temperature |
-20 deg C to +120 deg C (-4 deg F to +248 deg F) |
Material Thermal Limit |
|
Face-to-Face Dimension |
EN 558 Series 20 / API 609 |
Standardized Interchangeability |
|
Flange Hole Alignment |
ANSI B16.5 Class 150 / EN 1092-1 PN10 / JIS 10K |
Multi-Standard Slot Pattern |
|
Top Flange Mounting |
ISO 5211 (F05 to F12 depending on size) |
Direct Automation Standard |
|
Seat Leakage Rate |
Rate A (Zero Leakage) |
ISO 5208 / EN 12266-1 |
Materials & Media Compatibility
Component Metallurgy & Polymers
|
Part Name |
Standard Material |
Optional Material |
|
Body |
Virgin PVDF |
- |
|
Disc |
Molded PVDF |
PVDF with SS316 Insert Core |
|
Stem / Shaft |
Stainless Steel 304 / 316L (Encapsulated) |
Titanium Grade 2 / Hastelloy C-276 |
|
Seat Seal |
EPDM |
FPM (Viton) / PTFE-Encapsulated EPDM |
|
Stem Bushing |
PTFE / PVDF |
PVDF |
Media Resistance Ratings
Compatible: Hydrochloric acid (<= 37%), sulfuric acid (<= 98%), nitric acid (<= 65%), wet chlorine gas, sodium hypochlorite, ultra-pure water (UPW), deionized water.
Not Recommended: Fuming sulfuric acid (Oleum), strong hot caustic soda (>= 50% at > 90 deg C), acetone, ethyl acetate, liquid fluorine.
Connection & Configuration Options
Wafer Style
Slotted bolt holes align with ANSI Class 150, EN 1092-1 PN10, and JIS 10K flanges. Reduces line weight and space requirements.
Lug Style
Threaded inserts allow single-flange downstream isolation and dead-end piping maintenance without line pressure loss upstream.
Manual Control Options
Hand Lever: Multi-position notch plate (DN40-DN150) for rapid open/close and throttling lock.
Worm Gearbox: Cast iron or molded polymer housing with handwheel for controlled torque operation (DN200-DN300).
Actuation Interfaces
Pneumatic: Double-acting or single-acting spring-return actuators with NAMUR solenoid valve mounting.
Electric: On/off or modulating (4-20 mA input) units with ISO 5211 bolt circle alignment.
Application-Specific Design Considerations
Pressure-Temperature Derating: PVDF mechanical strength decreases as system temperature rises. Operating pressure must be derated for elevated process temperatures:
|
Temperature (deg C) |
Maximum Allowable Working Pressure (Bar) |
|
-20 to 20 |
10.0 |
|
40 |
8.2 |
|
60 |
6.5 |
|
80 |
4.8 |
|
100 |
3.2 |
|
120 |
1.5 |
Thermal Expansion Management: Linear thermal expansion of PVDF (0.12 mm/m*K) is higher than metallic piping. Piping alignment must accommodate axial thermal movements to prevent flange side-loading on the valve neck.
Cavitation and Throttling: Continuous operation below 15 deg open angle causes localized high velocity, risking cavitation erosion along the seat seal edge.
Technical Support: Need detailed flow curves or custom pressure calculations?
Applications
Semiconductor Manufacturing: Control and isolation lines for Ultra-Pure Water (UPW) systems and chemical delivery units.
Chemical Processing: Handling pickling acids, aggressive chlor-alkali fluids, and mixed acid waste streams.
Industrial Wastewater Treatment: Neutralization lines, acid-dosing stations, and heavy metal recovery plants.
Desalination & Marine Systems: High-salinity brine handling, seawater electrolysis, and hypochlorite injection.
Electroplating & Surface Treatment: Acid baths, rinse water circulation, and electroplating solution lines.
Quality & Inspection
Raw Material Verification: Melt flow index (MFI) testing and density checks per batch to confirm raw virgin PVDF resin purity.
Dimensional Inspection: CMM verification of body face-to-face dimensions, stem alignment, and ISO 5211 top-flange tolerances.
Shell & Seat Pressure Testing:
- Shell hydrostatic test: 1.5x PN (15 bar / 217 psi) for 60 seconds per ISO 5208.
- Seat pneumatic/hydrostatic leak test: 1.1x PN (11 bar / 160 psi) for zero-bubble shutoff.
Surface Roughness Measurement: Surface profiling for high-purity variants to ensure wetted surfaces achieve Ra <= 0.8 micrometers.
OEM / ODM & Customization
Custom Flange Standards: Adaptations for non-standard bolt circle diameters or special face-to-face requirements.
Custom Brand & Tagging: Laser-engraved stainless steel tags, custom body color markings, and private label handwheel plates.
Actuator Integration: Pre-assembled and bench-tested actuation packages (pneumatic/electric) including limit switches, positioners, and solenoid valves.
Special Material Sourcing: Custom seal formulations (e.g., peroxide-cured EPDM, specialized fluorocarbon grades) for specific chemical mixtures.
Custom Projects: Require custom labeling or integrated actuation assembly?
FAQ
Q: What is the main operational difference between PVDF and PVC butterfly valves?
A: PVDF withstands higher temperatures (up to 120 deg C vs. PVC's 60 deg C) and higher concentrations of strong acids and oxidizers. PVDF also offers superior mechanical strength and lower chemical leaching in pure water lines.
Q: Can this PVDF butterfly valve be used for vacuum service?
A: Standard wafer units operate safely down to partial vacuum levels (0.8 bar absolute). For full vacuum applications (< 0.1 bar absolute), internal seal retention configurations must be confirmed to prevent seat movement.
Q: How do I choose between EPDM, FPM, and PTFE seats for PVDF valves?
A: Use EPDM for dilute acids, alkalis, and hot water lines. Use FPM for concentrated acids, oils, and aromatic hydrocarbons. Choose PTFE-encapsulated seats for highly oxidizing chemicals or mixed chemical streams where elastomeric compatibility is limited.
Q: Are the flange dimensions compatible with both US ANSI and European DIN standards?
A: Yes. The valve body uses slotted bolt holes designed to fit ANSI Class 150, EN 1092-1 PN10, and JIS 10K flange patterns without modifying the body casing.
Q: Is a stem extension available for insulated piping lines?
A: Stem extensions are available in custom lengths. They raise the ISO 5211 mounting pad and actuator clear of pipe insulation layers while preserving stem torque transmission.
Q: What torque values should be used when mounting an actuator?
A: Operating torque depends on size and line pressure. A baseline DN100 (4") valve requires approximately 45 N*m operating torque at 10 bar differential pressure. We provide specific torque curves based on medium viscosity and differential pressure upon request.
Hot Tags: pvdf butterfly valve, China pvdf butterfly valve manufacturers, factory
Send Inquiry
You Might Also Like
